Hydraulic elevator.



No. 667,4l8. I Patented Feb. 5, WI. F. -A. BATES.

HYDRAULIC ELEVATOR.

Application filed Nov. 6,, 1897.) (No Model.)

Attorney.

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NITED STATES.

FRANCIS A. BATES, OF PHILADELPHIA, PENNSYLVANIA, ASSIGNOR TO THE MORSE,WILLIAMS & COMPANY, OF PENNSYLVANIA.

HYDRAULIC ELEVATOR.

SPECIFICATION forming part of Letters Patent no. 667 ,418, datedFebruary 5, 1901.

Application filed November 6,1897. Serial No. 657,598. (No model.)

To all, whom, it may concern:

Be it known that I, FRANCIS A. BATES, of the city and county ofPhiladelphia, in the State of Pennsylvania, have invented an Improvementin Hydraulic Elevators, of which the following is a specification.

My invention has reference to hydraulic elevators; and it consists ofcertain improvements which are fully set forth in the followingspecification and shown in the accompanying drawings, which form a partthereof.

The object of my invention is to provide a suitable construction ofapparatus and method of operating the same fol-lifting heavy 5 and lightloads under proportional powers, whereby economy in cost of apparatusand small size thereof may be secured.

More specifically explained, my invention comprehends the employment ofa hydraulic 2o cylinder adapted to work undera pressure of, say, onehundred and ten pounds to perform the normal and usual work and when anexcessive load is required to be elevated increasing the powerautomatically while employing the same pump, so that this large load maybe raised with equal facility. This enables the use of a small pump andgives greater capacity to the ordinary construction of hydraulicelevators.

0 In carrying out my invention Iemploy two accumulator-tanks in whichwater is forced under pressure against a volume of inclosed air and inwhich one tank has approximately twice the pressure in normal operationof that 5 contained in the other. These tanks are connected by suitablepipes with a valve of novel construction arranged adjacent to thehydraulic or lifting cylinder for the elevator, so that either one maybe brought into communication with the hydraulic cylinder. Furthermore,I employ a source of water-supply, such as a large tank which receivesthe return water from the hydraulic cylinder in the usual manner, andthis I connect by a suc- 5 tion-pipe with an ordinary steam-pu mp,preferably a duplex pump. The discharge from this pump I connect withboth accumulatortanks, the connection with the high-pressure tank beingthrough a check-valve and the connection with the low-pressu re tankbeing through an automatic valve which closes the communication when themaximum pressure of the tank is secured. Furthermore, I provide a pipeconnection between the low-pressure tank and the suction side of thepump and insert therein a similar automatic valve connecting with thehigh-pressure tank in such a manner that communication by said pipe iscut off whenever the high-pressure tank contains a maximum pressure. Ifur 6o ther provide the steam-pu mp with automatic control-valves forstopping and starting it or changing its speed, which are operated bypressure in pipes in communication, respectively, with the high and lowpressure tanks. In addition to these features of construction I arrangea check-valve in the discharge between the low-pressure tank and thevalve of the hydraulic cylinder and a similar check-valve in theimmediate dis- 7o charge from the reservoir or source of supply of thewater. The method of operation of this apparatus after being brought toan operative condition is as follows: If alight load is to be lifted,the movement of the valve of the hydraulic cylinder will permit thewater under the pressure contained in the low-pressure tank toactuatethepiston ofthe hydraulic cylinder. As the pressure in the tankdecreases the automatic valve in the supplypipe thereto will open andwater under the pressure of the pump will find its way into the saidlowpressure tank to restore its pressure, and upon reaching its maximumpressure the automatic valve will close and the pump stop. In thismanner the supply of water is made commensurate with that used in thehydraulic cylinder.

If a heavy load were being raised by the elevator,the operation of thecontrol-valve would throw the high-pressure tank into communication withthe hydraulic cylinder and reduce* its pressure. The reduction of thispressure in the high-pressure tank not only starts the pump, butautomatically operates the valve 5 between the low-pressure tank and thesuction side of the pump, so as to supply the pump with water underpressure from the low pressure tank. In this manner the pump may usesmall steam-cylinders and yet have caroo parity on account of thepressure of the suction side to discharge the water against the maximumpressure of the high-pressure tank. In this manner the transfer of thewater from the lowpressure tank to the high-pressure tank to restore thepressure in the latter is automatically made.

By my improved construction a plant having the usual maximum liftingcapacity may have that capacity doubled with the same apparatus bysimply adding the second or high-pressure tank with the necessaryadditional pipes and valves at an additional cost, which is very smallas compared with that which would be necessary with a larger apparatusacting directly for heavy loads. Furthermore, it is far more economical,since for eight-tenths of the time only light loads would have to belifted. With my improved apparatus no more water is circulated than isabsolutely essential for the duty.

My invention will be better understood by reference to the accompanyingdrawings, in Which Figure 1 is a plan view showing my improvedapparatus. vations of the control-valve for the hydraulic cylinder. oneof the automatic valves, and Fig. 5 is a stead of steam-power.

Ordinarily the tank F will contain the water pumped in against theair-pressure with a maximum pressure of about one hundred and ten poundsper square inch, while the pressure in the tank G may rise to twohundred pounds. The discharge-pipeD from the pump connects by a branchwith both the tanks F and G, the connection with tank G being through acheck-valve E, permitting entrance of water into the tank G, but notfrom it. The connection of the pipe D with the tank F is through anautomatic valve H, to be hereinafter described. The suction-pipe 0,intermediate of the check-valve L and pump,

isco'nnected by a pipe J with the tank F, and

this pipecontains an automatic valve K, similar in construction to thevalve H.

Q is the hydraulic lifting-cylinder, of the well-known construction,which by means of suitable cables operated by its piston raises orlowers the cage or platform; (Not shown.) P is the control-valvethereof, adapted to supply water under the pressure of the tank F ortank G to the cylinder Q. The valve P connects with the tank F by meansof a pipe 0, containing a check-valve R to per- Figs. Zand 3 aresectional ele- Fig. 4 is a sectional elevation of mit the water to flowto the valve, but not backward, and by a second pipe 0 with the tank G.

I will now refer to the control-valve construction, although the same isnot specifically claimed in this application, since it forms thesubject--matter of my Patent No. 599,466, dated February 22, 1898. Thevalve consists of a cylinder T, having a port P leading to the cylinderQ, a discharge-portt at the bottom, two supply-ports 0 0, connectingwith the supply-pipe O, and a further port 0 connecting with thesupply-pipe 0. The valve-rod is provided with three pistons P P P Thesepistons are so spaced that when the valve-rod is moved so that theyoccupy the position shown in Fig. 2 the pressure from the pipe 0 iscounterbalanced between the pistons P and Pflwhile the waterfrom thepipe 0 passes through the check-valve R and by port 0' into the cylinderT, and thence out by the port P to the hydraulic cylinder Q. If thevalve-rod be moved downward to the position shown in Fig. 3, we willthen have the ports 0, 0', 0 and P in direct communication with the pipe0'. The water under high pressure then passes by pipe 0 through planview showing my improvements adapted to electric motors for operatingthe pump in- 1 these several ports and the connecting portion of thepipe 0 through the port P into i the cylinder Q. This enables thesame-sized A is the usual reservoir or tank into which piston therein toperform almost double the work on account of the excess of the pressureapplied thereto. The check-valve R prevents the pressure from the pipe 0exerting its influence back into the tank F. By mov ing the valve-rodsufficiently high, so that the piston P is moved above the port P thecontents of the cylinder Q is discharged backward through the port. Pand out of the bottom t of the valve-cylinder T and may be returned tothe tank A by a suitable pipe in the usual manner. .It will thus be seenthat if the pistons of the control-valve are only moved to permit waterto enter from the pipe 0 into the cylinder Q and then discharge theelevator will be operated under low pressure as often as required. If,however, a very heavy load is upon the cage, which might occur half adozen times or more a day, then the pistons are moved downward, so as toput the pipe 0 into communication with the port P and thus double thepower of the elevator.

M is the steam-pipe, communicating with the steam-cylinder of the pumpthrough two branches, in which are placed, respectively, valves N N, ofsuitable automatic construction-for example,similar in generalconstruction and operation to the valve H. These automatic valves areall controlled by the pressures in the tanks F and G, as follows: Thevalve K is governed by the pressure from the tank G through asmall pipeis, and likewise the valve N is controlled by the same pressure throughapipe n. The valve N is controlled by the pressure from the tank F,exerted through a small pipe n. The

valve H is controlled by the pressure existing in the tank G byconnecting with the pipe is, leading therefrom, by means of a pipe h.The construction of these automatic valves is shown in Fig. 4. Theyconsist of a cylinder H, into, which the two main pipes open. Apiston-valve H is movable in the cylinder, so as to open or close theorifices to the pipes leading thereto, and hence said piston operates asa balanced valve. A second cylinder H is arranged below the cylinder Hand contains a piston H directly connected with the piston-valve H. Aspring S tends to move the valve under a predetermined pressure and iscounteracted in its effect to a greater or less extent by the pressureof the water in the cylinder H exerted through the pipe h. It isself-evident that these automatic valves may be operated by the pressureof the water or by the pressure of the air in the tanks F G above thewater, as the operation and results would be the same. Any suitableconstruction of automatic valve may be employed in lieu of that shown.

In describing the valve H, I have in efiect described all of the valvesK, N, and N, as they all operate on the same principle.

The passage through the valve H registers with the pipes controlled byit at the highest point of its movement, whereas the piston through eachof the other regulating-valves will so register at the lowest point ofthe movement; otherwise the general construction of the valves may bethe same in practice.

The operation of the apparatus will now be clearly understood. Assumefirst that the pressure in the tank F has been raised to one hundred andten pounds per square inch and in the tank G to two hundred pounds persquare inch as a preliminary matter. If now the valve P is moved, so asto draw water from the tank F, it may be operated several times beforethe pressure in that tank is materially reduced. When the pressure inthe tank Ffalls to any appreciable extent, the pressure in the valve Nis reduced and automatically permits this valve to open and put the pumpB into operation. Water is then pumped from the tank A through the pipeD and thence through valve H into the tank F to supply that which isbeing drawn off. When the pressure in the tank F again reaches onehundred and ten pounds, the valve N closes the steam-supply and the pumpB stops. The operation of the pump is therefore automatic. Now assumingthat a heavy load is to be lifted the valve P is operated to permitwater 10 flow from the tank G. The effect of this is to lower thepressure in the tank G. Several operations of the cylinder Q might lowerthe pressure to, say, one hundred and eighty pounds; but when lowered toany material extent below two hundred pounds it is desirable to have thepressure increased again as soon as possible. When the pressure fallsbelow, say, one hundred and ninety-seven pounds, the valve Kautomatically opens. When this is done, the pressure in the suction-pipeO and in the pipe J increases to one hundred and ten or that of the tankF. The valve H remains closed whenever the pressure in the tank G fallsbelow two hundred pounds or the pressure predetermined for said tank,but is automatically opened when this pressure is reached, so that thetank F may receive further supply of water if its pressure of onehundred and ten pounds has been lowered at a time when the pressure ofthe tank G is a maximum. The falling of the pressure in the tank Greduces the pressure in the pipe n and this permits the valve N to openand supply steam to the pump B. Once more the pump is put intooperation, only that now the pressure of the suction-supply of the pumpis one hundred and ten pounds, and hence the pump has a capacity, withits assisted suction, to force the water through the pipe D andcheckvalve E into the tank G to bring the pressure back to two hundredpounds. The proportions of the tanks F and G should in practice hepreferably such that whenever water is taken from the tank F andtransferred to the tank G to increase its pressure again to two hundredpounds this is done Without decreasing the pressure of the tank F to'below, say, eighty ,pounds. As soon as the pressure is increased in thetank G the valves K and N automatically close and valve H opens.However, the valve N has been opened, because the pressure in the tank Gwas below one hundred and ten pounds. The water is then drawn from thetank A and delivered through the pipe D and valve H into the tank F, soas to return its pressure to one hundred and ten pounds. In this mannerthe working pressures of the two tanks F and G may be maintainedcontinuously within practical limits. The adjustment of the valves H K NN may be such that they are caused to operate under smaller differencesor variation of pressure in the tanks F and G, so that the difierencesin the pressure of these respective tanks may be so proportioned asnever to vary by more than ten pounds-that is to say, the pressure inthe tank F might never fall below one hundred pounds and thatin the tankG below one hundred and ninety pounds.

The proper proportioning of the tanks to the hydraulic cylinder of theelevator for a given number of possible operations under normalconditions would limit the possibility of lowering the pressure in thetanks below the figures above given or those determined in designing theapparatus. The adjustment of the spring S of the automatic valves willdetermine the maximum pressures which the tanks F and G would be made tosustain, as these springs govern the operation of the valves to insurethe pumps acting the moment the predetermined pressures of the tanks arereduced.

In place of operating the pump B by steam it may in some cases beoperated by electric power, as shown in Fig. 5. In this case B is anelectric motor which operates the pump proper. M is a supply electriccircuit containing two branches, each of which is provided withcircuit-closing switches, s representing a switch in one branch and s aswitch in the other branch. M is the return-circuit from the motor. S isan automatic switchoperating device corresponding to the valve N of Fig.1 and operates the switch 3. This device is operated by the pressureinthe tank F through the pipe 02. S is the operating device for moving theswitch 3 and is operated by the pressure in the tank G through the pipe71.. The cylinder H piston H and spring S would be the same in thedevices S S as in the valves H K N N; but the piston H would besubstituted by the connection with the switches s s to complete theelectric circuit in lieu of supplying the steam. The principle ofoperation, however, is identical.

In originally filling the tanks with water this may be done bycontrolling the automatic valve H by hand; but before that, when thereis no pressure, the pump may be made to operate to fill the tank G up toat least one hundred and ten pounds. The automatic valve H would then betemporarily adjusted by hand, so as to enable the pressure in tank F tobe raised to one hundred and ten pounds or more. After this theapparatus would work automatically, provided the supply of the tank F issufficiently great to maintain its pressure while raising the pressurein the tank G to its maximum. If not, then the pressure in the tank Gshould be raised as far as the pump will perform the duty and the valveH then once more controlled by hand to again raise the pressure in thetank F, so that the operation of the apparatus may again be proceededwith, each time using the pressure of the tank F to increase thepressure in the tank G under the action of the pump. After the apparatushas been once brought to an operative condition it will thereafter takecare of itself and continue to operate in the manner above described.

While I prefer the construction shown, I do not limit myself to thedetails thereof or to the particular arrangement of the parts, as thesemay be more or less modified or varied to suit the wishes of thedesigner.

Having now described my invention, what Iclaim as new, and desire toobtain by Letters Patent, is

1. In a hydraulic elevator, the combination of the hydraulic cylinder, ahigh-pressure tank, alow-pressure tank, pipes leading from the saidtanks to the hydraulic cylinder,means to open communication betweeneither of said tanks and the hydraulic cylinder, a pump, adischarge-pipe adapted to force water into each of the said tanks, asuction-pipe connecting the low-pressure tank with the suction side ofthe pump, a valve to control the' admission of water from the pump intothe low-pressure tank, an automatic valve to con trol the admission ofwater from the low-pressure tank into the suction-pipe of the pump, apower device to operate the pump, controlling nieans for regulating theoperation of the power device, and automatic devices controlled by thepressures within the tanks for governing the operation of the means forcontrolling the power device and for automatically opening the valves inthe supply-pipe and suction-pipe connecting with the lowpressure tank,permitting the passage of water when the pressures in the tanks fallbelow predetermined amounts.

2. In a hydraulic elevator, the combination of the hydraulic cylinder, ahigh-pressure tank, a low-pressure tank, pipes leading from the saidtanks to the hydraulic cylinder, means to open communication betweeneither of said tanks and the hydraulic cylinder, a pump, adischarge-pipe adapted to force water into each of the said tanks, asuction-pipe connecting the low-pressure tank with the suction side ofthe pn mp, a valve to control the admission of water from the pump intothe low-pressure tank, an automatic valve to control the admission ofwater from the lowpressure tank into the suction-pipe of the pump, apower device to operate the pump, controlling means for regulating theoperation of the power device, automatic devices controlled by thepressures within the tanks for governing the operation of the means forcontrolling the power device and for automatically. opening the valvesin the supplypipe and suction-pipe connecting with the low-pressure tankwhen the pressures in the tanks fall below predetermined amounts, awater reservoir or tank open to the atmosphere connecting with thesuction-pipe of the pump, and a check-valve interposed between the opentank or reservoir and the suctionpipe of the pump connecting with thelow-. pressure tank.

3. In a hydraulic elevator, the combination of the hydraulic cylinder, ahigh pressure tank, a low-pressure tank, pipes leading from the saidtanks to the hydraulic cylinder, means to open communication betweeneither of said tanks and the hydraulic cylinder, a pump, adischarge-pipe adapted to force water into each of the said tanks, asuction-pipe connecting the low-pressure tank with the suction side ofthe pump, a valve to control the admission of water from the pump intothe low pressure tank, an automatic valve to control the admission ofwater from the lowpressure tank into the suction-pipe of the pump, apower device to operate the pump, controlling means for regulating theoperation of the power device, automatic devices controlled by thepressures within the tanks for governing the operation of the means forcontrolling the power device and for automatically opening the valves inthe supplypipe and suction-pipe connecting with the tan-ks fall belowpredetermined amounts, and a cheek-valve in the discharge-pipe from thepump for the high-pressure tank to prevent the escape of water onceforced therein.

4. In a hoisting apparatus, the combination of a hydraulic cylinder, alow-pressure tank, a high-pressure tank, m ans for supplying water fromeither tank to the hydraulic cylinder, a pump for forcing water into thesaid tanks, a check-valve to prevent the flow of water from the high-pressure tank to the pump, an automatic valve to control the flow ofwater from the pump to the low-pressure tank, and means for supplyingthe pn mp with water under-atmospheric and also at a higher pressure.

5. In a hoistingapparatus, the combination of a hydraulic cylinder, alow-pressure tank, a high pressure tank, means for supplying water fromeither tank to the hydraulic cylinder, a pump for forcing water into thesaid tanks, a check-valve to prevent the flow of water from thehigh-pressure tank to the pump, an automatic valve to control the flowof water from the pump to the low-pressure tank, means for supplying thepump with water under atmospheric and also at a higher pressure, andmeans under the control of the pressure in the high-pressure tank forcontrolling said last-mentioned means whereby when the pressure in thehighpressure tank falls the pump is supplied with water at a pressureabove that of the atmosphere.

6. In a hoisting apparatus, the combination of a hydraulic cylinder, alow-pressure tank, a high-pressure tank, means for supplying water fromeither tank to the hydraulic cylinder, a pump for forcing water intosaid tanks, a check-valve to prevent the flow of water from the highpressure tank to the pump, an automatic valve to control the flow ofwater from the pump to the low-pressure tank, means for supplying thepump with water under atmospheric and also at a higher pressure, meansunder the control of the pressure in the high-pressure tank forcontrolling said last-mentioned means whereby when the pressure in thehigh-pressure tank falls the pump is supplied with water at a pressureabove that of the atmosphere, and a valve to control the operation ofthe pump governed by the pressure in the high-pressure tank whereby thepump operates when the pressure falls.

7. In a hoisting apparatus, the combination of a hydraulic cylinder, alow-pressure tank, a highpressure tank, means for supplying water fromeither tank to the hydraulic cylinder, a steam-pump for forcing waterinto the said tanks, a check-valve to prevent the flow of water from thehigh-pressure tank to the pump, an automatic valve to control the flowof water from the pump to the low-pressure tank, means for supplying thepump with water under atmospheric and also at a higher pressure, meansunder the control of the pressure in the high-pressure tank forcontrolling a pressure above that of the atmosphere, a valve to com rolthe operation of the pump governed by the pressure in the high-pressuretank, and a second valve to control the steam to the pump governed bythe pressure in the low-pressu re tank whereby the pump operates whenthe pressure falls in either tank.

8. In hyd raulie apparatus, the combination of a hydraulic power devicefor operating the elevator-cage, a primary tank open to the atmosphereand into which the water from the hydraulic power device discharges, alowpressure tank, a high-pressure tank, means under the control of theoperator on the elevator for supplying the hydraulic power device withwater from either the low or high pressure tank at will, a pump forpumping water from the primary tank into the lowpressure tank, pipesconnecting with the pump for withdrawing water from the lowpressure tankand delivering it into the highpressure tank, and automatic means forclosing the discharge from the pump to the lowpressure tank when pumpinginto the highpressnre tank.

9. In hydraulic apparatus, the combination of a hydraulic power devicefor operating the elevator-cage, a primary tank open to the atmosphereand into which the water from the hydraulic power device discharges, alowpressure tank, a high-pressure tank, means under the control of theoperator on the elevator for supplying the hydraulic power device withwater from either the low or high pressure tank at will, a pump forpumping water from the primary tank into the lowpressure tank, pipesconnecting with the pump for withdrawing water from the lowpressure tankand delivering it into the high- -pressure tank, and automatic valvedevices for closing the discharge from the pump to the low-pressure tankand opening the suction of the pump from the low-pressure tank whenpumping into the high-pressure tank.

10. In hydraulic apparatus, the combination of a hydraulic powordeviceforoperating the elevator-cage, a primary tank open to the atmosphereand into which the water from the hydraulic power device discharges, alowpressure tank, a high-pressure tank, means under the control of theoperator on the elevator for supplying the hydraulic power device withwater from either the low or high pressure tank at will, a pump forpumping water from the primary tank into the lowpressure tank, pipesconnecting with the pump for withdrawing water from the lowpressure tankand delivering it into the highpressure tank, automatic valve mechanismfor closing the discharge from the pump to the lowpressure tank whenpumping into the high-pressure tank, power device for operating thepump, and automatic controlling mechanism for regulating the operationof the power device operated by the pressure in both the low and highpressure tanks whereby the pump is automatically put into operation whenthe pressure in either tank falls below a definite amount.

11. In hydraulic apparatus, the combination of a primary tank orreservoir containing water, asecondary or low-pressure tank, pipesconnecting the low pressure and primary tanks, pumping mechanism forcirculating the water between the primary and low-pressure tanks andalso between the low and high pressure tanks, automatic mechanism underthe control of the pressure in the high-pressure tank for controllingthe pump in pumping into the high-pressure tank, and automatic mechanismunder the control of the pressure in the low-pressure tank forcontrolling the pump in pumping into the lowpressure tank.

12. In hydraulic apparatus, the combination of a primary tank orreservoir containing water, a secondary or low-pressure tank,-

pipes connecting the low-pressure and primary tanks, pumping mechanismfor circulating the water between the primary and lowpressure tanks andalso between the low and high pressure tanks, automatic mechanism underthe control of the pressure in the highpressure tank for controlling thepump in pumping into the high-pressure tank, automatic mechanism underthe control of the pressure in the low-pressure tank for controlling thepumpin pumping into the low-pressure tank, and power mechanism foroperating the pump undertne control of the pressures in both the highand low pressure tanks.

13. The combination with a hydraulic engine, of two supply-tankscontaining motor fluid at different pressures, a valve device wherebyeither tank can be put into connection with said engine, a pump forpumping fluid into said tanks, a supply or suction pipe leading from thelow-pressure tank to the pump, a valve to control the water flowing insaid pipe, and automatic means for closing the valve in the supply-pipewhen the pressure in the highpressure tank is increased,

substantially as set forth.

14. The combination with a hydraulic engine, of two supply-tankscontaining motor fluid at different pressures, a valve device wherebyeither tank can be put into connection with said engine, a pump forpumping fluid into said tanks, and meansfor automatically putting thesupply-pipe of the pump into communication with the low-pressure tankwhen the pressure on the'high-pressure tank decreases, substantially asset forth.

In testimony of which invention I hereunto set my hand.

F. A. BATES.

Witnesses:

R. M. HUNTER, D. U. GIBBO'NEY.

